1. ABUNDANCE AND DIET OF CRAYFISH IN TWO DIFFERENT HABITATS AT
GREENWING LABORATORY
Megan Petersohn, Kevin Geedey
Biology, Augustana College, Rock Island, IL 61201
Megan Petersohn
Augustana College
Rock Island, IL
MeganPetersohn11@augustana.edu
Contact
1. Loughman, Zachary J., and Thomas P. Simon. "Zoogeography, Taxonomy, And Conservation Of West Virginia's Ohio River Floodplain Crayfishes (Decapoda, Cambaridae)." Zookeys 74.Spec (2011): 1-78.
2. Page, L. The Crayfishes and Shrimps (Decapoda) of Illinois. Volume: 33 Article: 4
3. Voshell JR. Crayfishes. A Guide to Common Freshwater Invertebrates of North America. 2002. P 254-58.
References
Figure 2:
The average
crayfish
abundance
between habitats
Introduction
The findings provide insights into the behavior of crayfish in Main Pond at
Greenwing and ultimately, of crayfish elsewhere.
• Two different habitats demonstrated different patterns of crayfish abundance
but not diet, possibly because the available food does not differ between
different habitats of the same body of water.
• Crayfish abundance may not solely be dependent on one factor
• Findings are consistent with previous findings23 showing that the abundance
of crayfish determines the density of aquatic plant beds, or if plants are
present at all, implying that the high abundance of crayfish in the North
habitat caused the lack of vegetation.
• There was a general trend of not staying too close to shore, nor too far, and
not being in the shallow traps, nor the deeper traps.
• The crayfish may prefer the North habitat of Main Pond because it is much
more shallow or because of warmer temperatures and more light.
Discussion
Crayfish are very important for environmental biodiversity and can dramatically influence the ecosystem
they are apart of3. They are, however, one of the most imperiled animals in North America, primarily
from invasive species and habitat destruction1 but can withstand many forms of environmental stress like
temperature, pH, and alkalinity23. They will consume whatever available food there is because of their
omnivorous behavior23. They are known to significantly reduce aquatic plant life by cutting plants close
to their roots with the chelipeds but crayfish will also prey on snails, insects, scuds, small fish, fish eggs,
carrion, and other organic matter when vegetation is scarce3. By doing this, crayfish regulate the
environment and nutrients available for other organisms3.
Study Objectives
• Does crayfish abundance within a wetland differ between a shallow, open water habitat and a deeper,
vegetated habitat.?
• Because crayfish have a home range of 30 square meters, does crayfish diet within a wetland differ in
two different types of habitats?
Ultimately, I investigated the effects of two different habitats in the same body of water on the abundance
and diet of crayfish (Procambarus acutus) at the the Augustana Greenwing Environmental Laboratory in
Amboy, Illinois.
Habitat variation
• Proportion of vegetative cover was statistically different (Fig. 1)
• Proportion of cover in West habitat was significantly greater than the North
habitat
Crayfish abundance patterns
• Crayfish abundance varied between habitats, at different distances from the
shore, depths, and temperature
• More crayfish were caught in the North habitat than the West habitat (Fig. 2)
• More crayfish were caught at intermediate distances from shore (10 m) than were
caught either close to shore (5 m) or far from shore (15 m)
• Same pattern with depth and water temperature (Fig. 3)
• The least amount of crayfish were caught in the shallowest/warmest
and deepest/coldest ends of each habitat
Crayfish diet
• No statistical significance between habitats
Other variables
• No statistical significance of light penetration, SPC, TDS, or dissolved oxygen
levels and crayfish distribution in this pond
In general, the most crayfish were caught in the 10m-from-shore minnow trap in the
North habitat
Figure 1:
Average estimated
proportion of cover
between habitats
•Determine habitats
• Two habitats located in Main Pond at Augustana Greenwing
Environmental Laboratory and were 115 m apart
• North habitat – less vegetation, shallower, higher water temperatures
• West habitat – more vegetation, deeper, lower water temperatures
•Collection of crayfish
• Three minnow traps with canned cat food at each habitat
• Different distances from shore (5m, 10m, and 15m in each habitat)
• Traps were checked 11 separate times and each time, crayfish were
collected for analysis
•Record and analyze data
• Variables: Abundance, distance from shore, depth, diet, proportion of
vegetative cover, light penetrance, water temperature, specific
conductivity (SPC), total dissolved solids (TDS), and dissolved oxygen
•Diet analysis
• Dissection of gut – proportion of vegetation in gut and identifiable
material
North and West Habitats
Main Pond in Greenwing Environmental Laboratory (Amboy, IL)
West HabitatNorth Habitat
0
0.2
0.4
0.6
0.8
1
1.2
EstimatedProportionof
Cover
0
0.02
0.04
0.06
0.08
0.1
0.12
Abundance(catchpertrap
hour)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
20 30 40 50 60 70 80 90 100
Abundance(catchper
traphour)
Depth (cm)
ANOVA, F=353.33, P<6.9x10-39
North Habitat West Habitat
Results
Methods
ANOVA, F=7.15, P<.009
North Habitat West Habitat
Figure 3:
Crayfish
abundance at
specified trap
depths (above)
and different
temperatures
(below)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
18 19 20 21 22 23 24 25 26
Abundance(catchper
traphour)
Temperature (degrees Celcius)
ANOVA, F=6759.33, P<5.9x10-114